FIR: Preserve K1 behavior for synthetic properties on raw type

^KT-54502 Fixed

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java

@@ -24223,6 +24223,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                     runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeInUpperBound.kt");
                 }
 
+                @Test
+                @TestMetadata("rawTypeSyntheticExtensions.kt")
+                public void testRawTypeSyntheticExtensions() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeSyntheticExtensions.kt");
+                }
+
                 @Test
                 @TestMetadata("rawWithInProjection.kt")
                 public void testRawWithInProjection() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java

@@ -24223,6 +24223,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                     runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeInUpperBound.kt");
                 }
 
+                @Test
+                @TestMetadata("rawTypeSyntheticExtensions.kt")
+                public void testRawTypeSyntheticExtensions() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeSyntheticExtensions.kt");
+                }
+
                 @Test
                 @TestMetadata("rawWithInProjection.kt")
                 public void testRawWithInProjection() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java

@@ -24223,6 +24223,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                     runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeInUpperBound.kt");
                 }
 
+                @Test
+                @TestMetadata("rawTypeSyntheticExtensions.kt")
+                public void testRawTypeSyntheticExtensions() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeSyntheticExtensions.kt");
+                }
+
                 @Test
                 @TestMetadata("rawWithInProjection.kt")
                 public void testRawWithInProjection() throws Exception {

compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt

@@ -29,6 +29,7 @@ import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.impl.ConeClassLikeTypeImpl
 import org.jetbrains.kotlin.fir.types.impl.ConeTypeParameterTypeImpl
+import org.jetbrains.kotlin.fir.types.lowerBoundIfFlexible
 import org.jetbrains.kotlin.resolve.calls.NewCommonSuperTypeCalculator
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.model.*
@@ -850,3 +851,18 @@ private fun ConeKotlinType.eraseAsUpperBound(
 
         else -> error("unexpected Java type parameter upper bound kind: $this")
     }
+
+fun ConeKotlinType.isRaw(): Boolean = lowerBoundIfFlexible().attributes.contains(CompilerConeAttributes.RawType)
+
+fun ConeKotlinType.convertToNonRawVersion(): ConeKotlinType {
+    if (!isRaw()) return this
+
+    if (this is ConeFlexibleType) {
+        return ConeFlexibleType(
+            lowerBound.withAttributes(this.attributes.remove(CompilerConeAttributes.RawType)),
+            upperBound,
+        )
+    }
+
+    return withAttributes(attributes.remove(CompilerConeAttributes.RawType))
+}

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/TowerLevels.kt

@@ -105,10 +105,31 @@ class MemberScopeTowerLevel(
         }
 
         if (givenExtensionReceiverOptions.isEmpty()) {
+            val dispatchReceiverType = dispatchReceiverValue.type
+
+            val useSiteForSyntheticScope: FirTypeScope
+            val typeForSyntheticScope: ConeKotlinType
+
+            // In K1, synthetic properties were working a bit differently
+            // - On first step they've been built on the per-class level
+            // - Then, they've been handled as regular extensions with specific receiver value
+            // In K2, we build those properties using specific use-site scope of given receiver
+            // And that gives us different results in case of raw types (since we've got special scopes for them)
+            // So, here we decide to preserve the K1 behavior just by converting the type to its non-raw version
+            if (dispatchReceiverType.isRaw()) {
+                typeForSyntheticScope = dispatchReceiverType.convertToNonRawVersion()
+                useSiteForSyntheticScope =
+                    typeForSyntheticScope.scope(session, scopeSession, FakeOverrideTypeCalculator.DoNothing)
+                        ?: error("No scope for flexible type scope, while it's not null for $dispatchReceiverType")
+            } else {
+                typeForSyntheticScope = dispatchReceiverType
+                useSiteForSyntheticScope = scope
+            }
+
             val withSynthetic = FirSyntheticPropertiesScope.createIfSyntheticNamesProviderIsDefined(
                 session,
-                dispatchReceiverValue.type,
-                scope
+                typeForSyntheticScope,
+                useSiteForSyntheticScope,
             )
             withSynthetic?.processScopeMembers { symbol ->
                 empty = false
@@ -320,6 +341,7 @@ class ScopeTowerLevel(
                     (implicitReceiverValue.type as? ConeClassLikeType)?.fullyExpandedType(session)?.lookupTag == lookupTag
                 }
             }
+
             else -> {
                 bodyResolveComponents.implicitReceiverStack.lastDispatchReceiver()
             }

compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeSyntheticExtensions.kt

@@ -0,0 +1,24 @@
+// SKIP_TXT
+// FIR_IDENTICAL
+// FILE: Generic.java
+import java.util.List;
+
+public class Generic<T extends Generic> {
+    // Returns Raw type
+    public static Generic create() { return null; }
+    public List<String> getFoo() { return null; }
+
+    public T getChild() { return null; }
+    public List<Generic> getChildren() { return null; }
+}
+
+// FILE: main.kt
+fun main() {
+    val generic = Generic.create() // has a type of Generic<(raw) Any..Any?>
+
+    generic.getFoo() // has return type List<(raw) Any..Any?>
+    generic.getFoo()[0].<!UNRESOLVED_REFERENCE!>length<!> // Unresolved "length"
+    generic.foo[0].length // OK
+
+    generic.child.children[0].foo[0].length // OK
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java

@@ -24229,6 +24229,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeInUpperBound.kt");
                 }
 
+                @Test
+                @TestMetadata("rawTypeSyntheticExtensions.kt")
+                public void testRawTypeSyntheticExtensions() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/rawTypeSyntheticExtensions.kt");
+                }
+
                 @Test
                 @TestMetadata("rawWithInProjection.kt")
                 public void testRawWithInProjection() throws Exception {